Driven largely by smart phones, tablets, and video streaming, the amount of wireless data handled by wireless networks has risen markedly and is expected to continue to rise by orders of magnitude over the next ten years. In addition to the sheer volume of data, the number of devices is expected to continue to grow exponentially, possibly reaching into the billions of devices, along with radically higher data rates. Different applications will place different requirements on the performance of future wireless networks. Future wireless networks are expected to be highly flexible, highly efficient, open, and customizable for customers and consumers.